171178-47-5

6313-33-3

58483-95-7

171178-47-5

5-Amino-2-chloropyridine-4-carboxylic acid (1000 g, 5.8 mol) and formamidine hydrochloride (1867 g, 23.2 mol) were mixed in ethylene glycol monomethyl ether (5000 mL) and sodium acetate (2360 g, 17.4 mol) was added. The reaction mixture was heated to 120 °C and maintained at this temperature for 6 hours. After completion of the reaction, it was cooled to room temperature and the reaction solution was poured into water (4000 mL) and extracted twice with ethyl acetate. The organic phases were combined, dried and concentrated to give the crude product. The crude product was filtered to give 6-chloropyrido[3,4-d]pyrimidin-4(3H)-one (924 g, 5.1 mol).